>>96156514yeah, totally hollow. There's just not that much to fill that space if you don't sit down for a long while with the DM and that parituclar DM has some interest in doing something that is actually playable. You can play them as re-skinned humans because humans don't have anything either. There are some cultures in the PHB but those are ignored and kinda hard to implement for a DM that doesn't care about FR. In a game set in 1600's Europe an italian, a spaniard and a briton would be totally different characters to play, from fight styles to cloting or meals they'd cook. If you wanted that experience in 5e you'd need a DM that's putting a ton of love and care into their craft and they could get burne at any point by players used to culture not being a thing.
Elves and dwarves have some stuff out of pop culture, they are popular among people who want to actually role play for that reasson. But I don't think it's a good thing that you need to tacitly agree on the most luke warm vanilla of possible settings. Tieflings at least have a connection with devils and demons, you could do something with that if you wanted. Dragonborn are probably the worst our of the PHB because there is no pop culture reference and I don't think any manual does anything with them. What even are they? Where do they live? What do they eat? How does the world see them?
Everything after the first Volo book is just re-skinned humans. For me plasmoids are the worst because they are an absolutely alien thing and there is no explanation of where they come from or what their deal is. Are they a failed experiment? Do they come from an all plasmoid world? Are they predators? Do they build houses or live in caves? Is each one a different existence that happened to evolve in the same direction? How do you role play something like that without constant exposition?